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calculate vote similarity using jaccard instead of cosine distance

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This commit is contained in:
r888888888
2017-04-13 14:07:20 -07:00
parent 602a7795f9
commit 62fde705ce
1 changed files with 11 additions and 1 deletions
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12
app/logical/post_vote_similarity.rb
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@@ -29,7 +29,7 @@ class PostVoteSimilarity
PostVote.positive_user_ids.each do |uid| PostVote.positive_user_ids.each do |uid|
posts1 = PostVote.positive_post_ids(uid) posts1 = PostVote.positive_post_ids(uid)
score = calculate_with_cosine(posts0, posts1) score = calculate_with_jaccard(posts0, posts1)
if score >= THRESHOLD if score >= THRESHOLD
set << Element.new(uid, score) set << Element.new(uid, score)
end end
@@ -38,6 +38,16 @@ class PostVoteSimilarity
set.sort.reverse.first(limit) set.sort.reverse.first(limit)
end end
def calculate_with_jaccard(posts0, posts1)
a = (posts0 & posts1).size
div = posts0.size + posts1.size - a
if div == 0
0
else
a / div.to_f
end
end
def calculate_with_cosine(posts0, posts1) def calculate_with_cosine(posts0, posts1)
a = (posts0 & posts1).size a = (posts0 & posts1).size
div = Math.sqrt(posts0.size * posts1.size) div = Math.sqrt(posts0.size * posts1.size)